Rescuing an instance

OpenStack Compute provides a handy troubleshooting tool with rescue mode. Should a user lose an SSH key, or otherwise not be able to boot and access an instance, say, bad iptables settings or failed network configuration, rescue mode will start a minimal instance and attach the disk from the failed instance to aid in recovery. This applies to both Windows and Linux instances as this process essentially allows the mounting of the boot volume of your failed instance as a secondary disk to the rescue instance.

Getting ready

To put an instance into rescue mode, you will need the following information:

• The openstack command-line client

• The openrc file containing appropriate credentials

• The name or ID of the instance

The instance we will use in this example is cookbook.test.

How to do it…

To put an instance into rescue mode, use the following steps:

1. First, we will put the instance into rescue mode as follows:

   openstack server rescue cookbook.test
   

   This will present us with a temporary...